convert to 220v

[gundwane]

I am getting more electrical circuits into my garage. I have a table saw and a bandsaw that can be converted to 220v. They have 3/4 and 1 hp motors. According to the manual I can convert them to 220V. I am wondering if it worth changing them over to 220 from 115V. Would the performance of the saws be improved? Can anyone tell me the benefits of converting.

[PaulMarcel]

My previous table saw was convertable as is my current band saw. Those motors take 15A @ 120V or 7.5A @ 220V. For me, the biggest benefit was not popping the breaker on startup for the bandsaw, which happened *often*. It also definitely spins up faster since it can get the surge current needed to get those wheels moving. For the table saw, it wasn't that big a deal as it didn't pop the breaker on startup. Newer homes may have slower-blow breakers to handle startup surge currents, but mine pop when I sneeze. So, to me, the table saw conversion may not be worth it to you especially if you have to make a separate run and wire plugs/sockets. For the bandsaw, it's worth the work, IMHO

[Saddlestrum]

I agree with the previous post by Paul-Marcel. I converted my bandsaw and tablesaw to run on 220 volt. When I mentioned it to a local motor repair shop, they said the motors would last longer too because they are drawing 1/2 the amperage so I should see longer life out of the motors, all things being equal.

Before switching, my tablesaw would blow the breaker if pushing through harder material. The bandsaw was fine but did the conversion anyway.

Haven't converted the jointer as it seems to run just fine on 120...plus the fact the Delta manual says I need to buy a special switch to do the conversion.

[PaulMarcel]

I agree with the previous post by Paul-Marcel. I converted my bandsaw and tablesaw to run on 220 volt. When I mentioned it to a local motor repair shop, they said the motors would last longer too because they are drawing 1/2 the amperage so I should see longer life out of the motors, all things being equal.

Before switching, my tablesaw would blow the breaker if pushing through harder material. The bandsaw was fine but did the conversion anyway.

Haven't converted the jointer as it seems to run just fine on 120...plus the fact the Delta manual says I need to buy a special switch to do the conversion.

Oh, that's odd that for you it's opposite: TS needed it, bandsaw didn't. But great point on motor life. The Delta switch is likely a double-throw switch instead of a single-throw. If Delta's is too expensive, you certainly could get those elsewhere.

[wilburpan]

For me, the biggest benefit was not popping the breaker on startup for the bandsaw, which happened *often*. It also definitely spins up faster since it can get the surge current needed to get those wheels moving. For the table saw, it wasn't that big a deal as it didn't pop the breaker on startup. Newer homes may have slower-blow breakers to handle startup surge currents, but mine pop when I sneeze.

I had the same problem with popping breakers with my dust collector. I wound up replacing my Square-D circuit breakers with their "High Magnetic" equivalents, which are more tolerant of current inrush. That worked great. The only issue was that I had to go to a local electrical supply house to get them. The borgs don't carry these.

[knotscott]

You probably won't notice much difference in motors of that size....with motors of 1-1/2, 1-3/4hp there might be more of a difference, but it really depends on the particular motor and the circuit its running on. True 2hp+ motors really should be on a 220v circuits. 220v tends to have less voltage loss during peak demands, so it's usually more noticeable (if at all) on bigger motors that draw more amps. If you've got 220v already, it's only going to cost you a plug that's compatible with the 220v outlet.

Here's the way I understand it. Residential wiring consists of two 120v supply legs (aka 110v)....those supply legs get combined where there's a need for 240v (aka 220v) operation (larger motors, dryers, hot tubs, ovens, etc.), otherwise they're just split up to the various 120v circuits. The induction motors we use in tools have two windings....they either run in series (110v) or in parallel (220v). A motor running on 110v draws all of it's current from one 110v supply leg (say 15 amps shared between the two coils wired in series, each seeing roughly 7.5 amps)...wired for 220v the same motor would draw half the current per 110v supply leg (7.5 amps per leg), but it draws it through both 110v supply legs. The total amperage for the motor remains 15 amps, but it's achieved by two legs each supplying 7.5 amps instead of one leg supplying all 15 amps. Theoretically there should be no difference between how a motor runs on 110v or 220v if the circuits are wired properly. But if a particular 110v circuit isn't quite getting the job done due to being a very long run, was wired with undersized wires, has many junctions, or many appliances drawing from the same line, etc., then that line might struggle delivering full amperage, and could suffer some voltage loss, lights dimming, etc. Those are the moments when the motors tend to get subjected to added heat in the coils....it's also during those moments that a 220v line might be beneficial by being more capable of delivering the needed amperage with less loss, which would in turn avoid the additional heat. More often than not, the improvement from 220v is due to the fact that it's a dedicated line, and not shared by other appliances, but sometimes the improvement is real and noticeable.

Bottom line, if 220v is readily available, there's no harm in rewiring your motors for 220v, and there might be some benefit. If you don't have 220v, and you're not experiencing obvious effects from voltage drop on a 110v circuit, then there's really no need to bother with 220v. If you are experiencing lugging, lights dimming, etc., a dedicated circuited that's properly wired may solve the problem....if you're going to have a line run, I'd opt for 220v.

[gundwane]

Lots of good information guys. I appreciate it. I have not had any problems popping the breaker. I do plan on having the saws for some time so anything to help prolong there life would be a good idea. Motors are not cheap. I have been running my shop on one 20Amp circuit shared with the house and I don't have many outlets in the shop. Now I have 220 and a couple of 110 circuits. So I think I will evaluate what wiring will be needed and lean towards putting in 220. With the price of copper the costs add up in a hurry though.

[PaulMarcel]

One additional thought. I'm putting more runs in my garage likely over Thanksgiving weekend (so, give thanks for electrons!!) I have 2 runs planned and each is going to be 220V run with 12/3 wire. I plan on running 2 hots and neutral. I can then make some 110 circuits off the run (one hot, one neutral). This is particularly useful for my table saw. My saw is a 220V SawStop PCS with a router in the extension wing. I'll use a dryer plug/socket at the saw so I can have one power cord going to the saw, but break it up into 220 for the saw and 110 for the router (and 110 for the light attached to my overhead dust guard). Much cleaner that way. For the bandsaw, it will be similar except I'll make separate wall receptacles: one for the 220 bandsaw and a 110 for the dedicated DC and a 110 for the drill press (there are plugs there, but they share loads with a freezer; this gets them off house stuff).

My point is that I'll have 2 runs going to 2 breakers but get a number of 110 sockets by my 220 sockets so double-duty on the wire runs, which are the PITA.

[DALSAW]

My current shop has only 110 volt but thats running through an 30 amp breaker and a 8/2 wire so I don't have any problems running my 1 3/4 HP table saw or band saw. The new shop I'm building will have 220 volt but instead of converting my current machines to 220 I'm just going to replace them with higher HP machines.

[Beechwood Chip]

My point is that I'll have 2 runs going to 2 breakers but get a number of 110 sockets by my 220 sockets so double-duty on the wire runs, which are the PITA.

I asked an electrician about that once, and he said the only problem is that someone may need to work on a 110 line, turn off that breaker, and still get a shock because there's a 220 device plugged in and acting as a bridge from the other 110 circuit (the other half of the 220). It may not be code, and you might want to label it at each J-box. If you use a 220 double breaker where the two breakers are ganged together, I think it'll be OK.

I recently discovered half-height breakers. They are the size of regular breakers but have two complete breakers in that space. I needed a 220 line and was out of slots, so I used a double half-height breaker which can supply two 220 circuits, two 110 circuits and a 220, or four 110 circuits. In my case I pulled out two regular 110 breakers and used the double half-height for the two 110 circuits and the new 220.

[PaulMarcel]

Good point, Beech. I was assuming the double-ganged breakers. Actually, could you make a regular 220 circuit with 2 breakers? I guess when one tripped, the circuit woudl be broken. Anyway, I assumed the doubles so you'd have the whole 'wire' disconnected, includng any mix of 110/220 sockets you'd have on it. For me it would just make for a lot less conduit, less wire, and the planned loads are mutually exclusive. I do plan, however, on well marking the boxes so I know which circuits are shared so I can avoid popping more breakers.

[knotscott]

Good point, Beech. I was assuming the double-ganged breakers. Actually, could you make a regular 220 circuit with 2 breakers? I guess when one tripped, the circuit woudl be broken. .....

I'm way out of my element here Paul, so I could be completely wrong, but I was under the impression that breaking one of the 110v supply legs of a 220v line, will still give you 110v at one side of the outlet. My concern is that if I'm right, I'd hate to have you or anyone approach an assumed dead 220v line and find out the hard way that it's still half alive. Hopefully someone who knows for sure will shed some light.

[PaulMarcel]

Oh, definitely, if it was created using 2 breakers, only one will throw when it 'breaks' so the other leg would be hot. I think those ganged breakers throw together (hence even the switches ganged together with a bar).

I have room in my service panel so I was gonna get ganged breakers, but you certainly bring up the flaw in using 2 single breakers to create a 220 circuit. I just want to create 110 outlets on my 220 branch to save on stringing up more wire and additional breaker slots all while staying in the confines of a 20A limit.

[gundwane]

One additional thought. I'm putting more runs in my garage likely over Thanksgiving weekend (so, give thanks for electrons!!) I have 2 runs planned and each is going to be 220V run with 12/3 wire. I plan on running 2 hots and neutral. I can then make some 110 circuits off the run (one hot, one neutral). This is particularly useful for my table saw. My saw is a 220V SawStop PCS with a router in the extension wing. I'll use a dryer plug/socket at the saw so I can have one power cord going to the saw, but break it up into 220 for the saw and 110 for the router (and 110 for the light attached to my overhead dust guard). Much cleaner that way. For the bandsaw, it will be similar except I'll make separate wall receptacles: one for the 220 bandsaw and a 110 for the dedicated DC and a 110 for the drill press (there are plugs there, but they share loads with a freezer; this gets them off house stuff).

My point is that I'll have 2 runs going to 2 breakers but get a number of 110 sockets by my 220 sockets so double-duty on the wire runs, which are the PITA.

I am not an electrician. Although I have the basic understanding. I paid the electrician to get me a breaker panel for the garage and I am going to wire the rest myself. So I have a learning curve to go through. Now your making me think a little more. I was under the impression that the 220 and the 110 circuits would be separate starting at the panel. Never thought I could use one run for both. Would save on that expensive copper. Do you just put a box at your saw to do all the wiring inside of?

[PaulMarcel]

So I'm not much for drawing programs. Sharpies, printer paper and a ruler work for me. Your question had me draw out what I'll wire over Thanksgiving weekend so thanks for getting me off my butt

Here's a short description of a service panel:

I only had those colors so don't think "neutral" is "ground" just because I drew it in green (though it is in certain cases, but definitely not for this).

The sides of your panel are the hot rails from the power company. They are attached to the big bolts at the top of the panel that bring in 220V (btw, even when you flip the big switch for your panel, those bolts are hot and their 'breaker' is rated a little higher than you could tolerate). Middle is neutral; on a main panel, this happens to be strapped to ground, but always treat them as separate.

Note that the sockets I drew only show conductors; all would have a ground coming from the panel to their ground lug.

110V circuits in your house are wired with hot attached to the brass side of a socket (the smaller prong of a plug) and neutral to the aluminum side (the wide blade of a polarized plug). It doesn't matter if the hot comes from the left side or right side. You can see that in the first two sockets I drew on the diagram. Note the l-hot/r-hot are my designations and not electrician designations; it's for this discussion.

220V circuits use both hots; there is no "polarization" concept in a 220V socket so a hot goes on either side.

Older dryers had a 4-prong plug that brought both hots, neutral and ground to the dryer. The dryer used the hots to run the elements at 220V. It used the neutral to create a 110V circuit internally to run the electromechanical timer. Now days, you'll find a 220V-only socket for dryers as they all have solid-state timers and use the equivalent of a laptop power transformer to turn 220V to 5V.

So... for my table saw, I'm going to run 12/3 (12 gauge wire, 3 conductor plus ground) and make an old-time dryer socket that has the pin configuration you see in the picture. I'll get 12/3 stranded wire to create the extension cord pig-tail to the saw. Plug on one end to connect to the socket (duh) and the other end will go to a double-gang box on the saw (a metal box capable of holding 2 duplex sockets). I'll put a 220V socket there and plug the saw into it right there with the existing power cord. I'll also put a duplex 110V socket in the box. One socket will be for the router, the other for the light I put on my overhead dust arm.

This way I have 1 wire across the floor going to the saw. I'm running the new cable anyway because I need to so I may as well put the right sockets on it to make everything cleaner; it would honestly be more work to split the 3 conductors into a 220V socket and 110V socket on the wall and run 2 extensions to the saw.

Below is a sketch of my shop (not to scale ) showing 3 runs of 12/3 I plan on putting in and the sockets they'll service. The bandsaw branch also serves the dust collector/compressor on the other side of the shop simply because they will never need to be on at once (bandsaw has its own DC serviced by the branch, though). Saw/Router are another branch with the planer (again all mutually exclusive). Last is a run for the window A/C unit I run in the summer. It'll supply two 110V outlets: one for the miter saw and one for a task light on my bench.

As for breaker size; yes, when I run the router all on its own, it will be on a 20A circuit though it really shouldn't draw more than 15A. Some would say that's bad cuz the safety cut-off is above the rated max, but actually current code is that outdoor receptacles must be GFCI and 20A (oh, my 110V circuits shown here will be GFCI protected; it's smart to do though more costly).

Hopefully this clears up some of the thoughts. Thanks for making me draw it out before next week; gives me a head start on purchasing conduit and wire!

EDIT: I'm not a licensed electrician, but I've done a fair amount of trivial and not so trivial wiring. That said, I still think I'll put up the conduits and string the wire then have an electrician come over to verify everything and, especially, do the service panel work (q.v., those big bolts...). If you decide to do this, make sure you understand it and have someone look it over who knows. Your mileage may vary. No animals were harmed in this posting. Operators standing by.

I plan on taking a lot of pictures and documenting it all on my blog since this stuff comes up often. It indirectly gets reposted here to the blogs page.

Edited November 19, 2010 by Paul-Marcel
disclaimer and plug (-snicker-)

[SignWave]

Paul-Marcel, you can do what you're proposing, more or less, but you really need to install a sub-panel. It is the same basic idea as your first diagram, but with breakers in between the feed and the branch circuits.

This won't cost much, and it will still accomplish your desired end result, but in a way that is code compliant.

[BuilderBill]

I asked an electrician about that once, and he said the only problem is that someone may need to work on a 110 line, turn off that breaker, and still get a shock because there's a 220 device plugged in and acting as a bridge from the other 110 circuit (the other half of the 220). It may not be code, and you might want to label it at each J-box. If you use a 220 double breaker where the two breakers are ganged together, I think it'll be OK.

I recently discovered half-height breakers. They are the size of regular breakers but have two complete breakers in that space. I needed a 220 line and was out of slots, so I used a double half-height breaker which can supply two 220 circuits, two 110 circuits and a 220, or four 110 circuits. In my case I pulled out two regular 110 breakers and used the double half-height for the two 110 circuits and the new 220.

You have to be careful when pulling 220 circuits with half-height breakers. You can legally do that but the half-breakers serving the 240v circuit would have to be physically adjacent to each other and have the handles mechanically tied together. That's the ONLY way to be safe and legal in this instance. Basically, code requires that you go to the panel, trip one handle and anything attached to that circuit is dead, period, end of story. If you don't have the handles physically tied together someone working on the circuit could turn off one breaker, check for 220(which isn' t there since one breaker is off) and take a full-current jolt(i.e. get his/her ass fried) off the remaining 110 leg(building codes aren't just words written in a book somewhere, they're adopted as the law of the land in the appropriate jurisdiction).

Now you get to meet all sorts of interesting folks like bailiffs, court recorders and judges and your HO insurance agent is standing in the back of the court snickering because YOU broke the law. And this could all happen years after you sold the house and moved on.....

Pulling a 110 outlet off a 220 circuit is fine, you just have to remember that pulling more than rated amperage off either leg of the circuit will trip the breaker. In a one-man shop that's not likely to happen unless you wire the dust collector for 220 and then fire up a 110 tool on that same circuit. Then it's a trip to the panel... But if you have a buddy or, God forbid, a paid employee working with you that's more likely to happen than with just you by yourself. Nothing you can't deal with but who needs to keep running back and forth to the panel when you could be working?

Another thing to consider is that most of us have our shops either in the garage or the basement, right? Both areas more than likely have concrete floors, right? Guess what? Code(that pesky law thing, remember?) requires that outlets in those areas have ground-fault protection. Did you put a GFCI circuit in for your 110 receptacles? Sure, you've got enough sense to not go barefoot on a wet concrete floor while operating electrical tools but can you say the same about Joe Schmoe who bought your house three years ago?

Maybe I'm just paranoid. I spent the first week of this month in court being sued by a dumbass who walked in pitch-black darkness into a garage in a house that I framed that didn't have a floor. He fell 9', hurt his left heel and right knee. Never spent a night in the hospital. He's 2% disabled. Jury gave him $300K between me and the GC. My liability? I didn't put up caution tape. Never mind the fact that there was all sorts of lumber stacked in front of the garage and rebar loops sticking up, it was dark as the Ace of Spades, he didn't have a flashlight, he violated his employers safety policy, I should have put up guardrails or caution tape even though no one had any legitimate business being in the house.... The only good thing about the whole experience is that if I ever get rear-ended I know which ambulance-chaser to call... And that my G/L insurance covered it all but I'm sure I'll see a rate adjustment next year.

I guess what I'm trying to say is that if you're going to dick around with your wiring, make sure you hire a licensed contractor and get permits for any modifications. If you don't, you could wind up in court like me without the benefit of an insurance company paying the $300/hr attorney and any damages. And that definitely wouldn't be a Good Thing. Actually, I'd say that would suck mightily....

Bill

[PaulMarcel]

Paul-Marcel, you can do what you're proposing, more or less, but you really need to install a sub-panel. It is the same basic idea as your first diagram, but with breakers in between the feed and the branch circuits.

This won't cost much, and it will still accomplish your desired end result, but in a way that is code compliant.

Thanks, SignWave... I posted that before driving 2 hours to a wedding in Tucson and along the way I thought about just doing a small subpanel where the three lines initially split off. Would make adding additional lines easier to monkey with. The runs to the outlets, though, I still would like to do them as proposed to cut down on pulled lines. Then on the way back, l got to thinking of a better way to distribute the receptacles.

So between thinking "hmm a subpanel would give more flexibility" and your reply, I'll go chat with the electrical supply people tomorrow morning and look up what gauge I'd need from the main panel to the sub and any conduit volume requirements.

And Bill-san, I have a bit of a loathing for our legal system since it seems "anti-Darwin" in that the stupid win big. That said, anything electrical that I haven't learned and done before, I get an electrician to look over to make sure everything is code, like handy tape markers and box volumes. (though coincidentally, my garage door has several wraps of caution tape on it just for fun )

Good luck with the case. I think I've suffered worse than his fall from recreational hockey; maybe I should sue the other team.